/**
 * @license Copyright (c) 2003-2023, CKSource Holding sp. z o.o. All rights reserved.
 * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license
 */
/**
 * @module list/documentlist/documentlistindentcommand
 */
import { Command } from 'ckeditor5/src/core';
import { expandListBlocksToCompleteItems, indentBlocks, isFirstBlockOfListItem, isListItemBlock, isSingleListItem, outdentBlocksWithMerge, sortBlocks, splitListItemBefore } from './utils/model';
import ListWalker from './utils/listwalker';
/**
 * The document list indent command. It is used by the {@link module:list/documentlist~DocumentList list feature}.
 */
export default class DocumentListIndentCommand extends Command {
    /**
     * Creates an instance of the command.
     *
     * @param editor The editor instance.
     * @param indentDirection The direction of indent. If it is equal to `backward`, the command
     * will outdent a list item.
     */
    constructor(editor, indentDirection) {
        super(editor);
        this._direction = indentDirection;
    }
    /**
     * @inheritDoc
     */
    refresh() {
        this.isEnabled = this._checkEnabled();
    }
    /**
     * Indents or outdents (depending on the {@link #constructor}'s `indentDirection` parameter) selected list items.
     *
     * @fires execute
     * @fires afterExecute
     */
    execute() {
        const model = this.editor.model;
        const blocks = getSelectedListBlocks(model.document.selection);
        model.change(writer => {
            const changedBlocks = [];
            // Handle selection contained in the single list item and starting in the following blocks.
            if (isSingleListItem(blocks) && !isFirstBlockOfListItem(blocks[0])) {
                // Allow increasing indent of following list item blocks.
                if (this._direction == 'forward') {
                    changedBlocks.push(...indentBlocks(blocks, writer));
                }
                // For indent make sure that indented blocks have a new ID.
                // For outdent just split blocks from the list item (give them a new IDs).
                changedBlocks.push(...splitListItemBefore(blocks[0], writer));
            }
            // More than a single list item is selected, or the first block of list item is selected.
            else {
                // Now just update the attributes of blocks.
                if (this._direction == 'forward') {
                    changedBlocks.push(...indentBlocks(blocks, writer, { expand: true }));
                }
                else {
                    changedBlocks.push(...outdentBlocksWithMerge(blocks, writer));
                }
            }
            // Align the list item type to match the previous list item (from the same list).
            for (const block of changedBlocks) {
                // This block become a plain block (for example a paragraph).
                if (!block.hasAttribute('listType')) {
                    continue;
                }
                const previousItemBlock = ListWalker.first(block, { sameIndent: true });
                if (previousItemBlock) {
                    writer.setAttribute('listType', previousItemBlock.getAttribute('listType'), block);
                }
            }
            this._fireAfterExecute(changedBlocks);
        });
    }
    /**
     * Fires the `afterExecute` event.
     *
     * @param changedBlocks The changed list elements.
     */
    _fireAfterExecute(changedBlocks) {
        this.fire('afterExecute', sortBlocks(new Set(changedBlocks)));
    }
    /**
     * Checks whether the command can be enabled in the current context.
     *
     * @returns Whether the command should be enabled.
     */
    _checkEnabled() {
        // Check whether any of position's ancestor is a list item.
        let blocks = getSelectedListBlocks(this.editor.model.document.selection);
        let firstBlock = blocks[0];
        // If selection is not in a list item, the command is disabled.
        if (!firstBlock) {
            return false;
        }
        // If we are outdenting it is enough to be in list item. Every list item can always be outdented.
        if (this._direction == 'backward') {
            return true;
        }
        // A single block of a list item is selected, so it could be indented as a sublist.
        if (isSingleListItem(blocks) && !isFirstBlockOfListItem(blocks[0])) {
            return true;
        }
        blocks = expandListBlocksToCompleteItems(blocks);
        firstBlock = blocks[0];
        // Check if there is any list item before selected items that could become a parent of selected items.
        const siblingItem = ListWalker.first(firstBlock, { sameIndent: true });
        if (!siblingItem) {
            return false;
        }
        if (siblingItem.getAttribute('listType') == firstBlock.getAttribute('listType')) {
            return true;
        }
        return false;
    }
}
/**
 * Returns an array of selected blocks truncated to the first non list block element.
 */
function getSelectedListBlocks(selection) {
    const blocks = Array.from(selection.getSelectedBlocks());
    const firstNonListBlockIndex = blocks.findIndex(block => !isListItemBlock(block));
    if (firstNonListBlockIndex != -1) {
        blocks.length = firstNonListBlockIndex;
    }
    return blocks;
}
